January 9, 2017, 6:54am I learned the hard way about gapping my B8ES plugs.... Gap them right the first time.
If you've got the BR8ES, get rid of them. #1 they're a Resistor plug and may not produce the right amount of spark. #2 the threaded end may come off in flight, ESPECIALLY if UPSIDE DOWN!
I have been using BR8ES plugs. I was about to switch over to B8ES based on above suggestion. But will the non resistor B8ES plugs affect / damage the CDI ignition ? I have read in some motorcycle groups that using a resistor plug protects other nearby electronics from interference. I also read elsewhere that using the non-resistor plugs may interfere with / damage the CDI ignition.
It is OK to use non-resistor plugs. They will not damage the CDI unit. Some engines also have resistor plug caps...the reason is to reduce the amount of radio frequency interference being produced by the spark.
I saw some comments as below from another power sports forum: (Which is the reason I asked ) This member's opinion may well be wrong, I agree.
MemberXXXX said: The resistor of the plug is intended to eliminate electrical noise which can cause problem and distortion with electronics and radio frequency like AM, etc. So... what does EMF noise do to your MPEM, and CDI unit ??? It can play all kinds of games with the electronics, as they run. So... you can misfire, and miss-interpret the ignition signal, casing it to fire at random timing.
The NGK website not say anything specifically about effect on CDI unit : ( Though it mentions possible misfire with non-resistor plugs )
FAQs - Spark Plugs
Q: When should I use a resistor spark plug?
A: NGK "R" or resistor spark plugs use a 5k ohm ceramic resistor in the spark plug to suppress ignition noise generated during sparking.
NGK strongly recommends using resistor spark plugs in any vehicle that uses on-board computer systems to monitor or control engine performance. This is because resistor spark plugs reduce electromagnetic interference with on-board electronics.
They are also recommended on any vehicle that has other on-board electronic systems such as engine-management computers, two-way radios, GPS systems, depth finders or whenever recommended by the manufacturer.
In fact, using a non-resistor plug in certain applications can actually cause the engine to suffer undesirable side effects such as an erratic idle, high-rpm misfire, engine run-on, power drop off at certain rpm levels and abnormal combustion.
Resistance will not worry any ignition system. When you consider the necessary voltages involved with creating the spark a few kilo-Ohms will not matter.
Resistance in the high tension wiring can reduce radio frequency standing waves, which will reduce emmission of radio waves, but not by a lot.
In the same way that it is necessary to label packets of peanuts as containing nuts, it is necessary to warn against a spark plug's ability to radiate radio waves which might upset an engine control system - whose designer was already very aware aware of such a possibility, and much more serious potential sources of radio wave energy.
Resistances included in plug caps reduce reliability of the spark occurring at all *when the resistance elements fail*. That is written as a statement because it has happened to me on two occasions.
Steel-capped spark plugs are safer than aluminium capped spark plugs because steel does not create as much conductive short-circuiting dust as do aluminium caps in a high vibration situation.
Personally I changed mine over to iridium spark plugs on all my engines (447, 462, 503) and haven't had any problems. The 447 is CDi, and the others are all points ignition. So far, the iridiums have meant easier starting, cleaner pick up, and smoother tick over. I gapped the points engine plugs to .5mm (around 20 thou) and the CDi engine plugs to .6mm (around 24 thou). The engines seem to like these gaps, and start and run nicely.
The iridiums I use are these, which are more expensive than standard BR8ES plugs, but to my mind quite a bit better (but that's just my opinion based on my own experience).
I was simply looking for a better plug. The BR8ES plugs don’t last very long. I think I will go in for the iridium plug BR8EIX. It costs $29.88 for a pack of 4. Good thing, it also is a resistor plug.
An interesting thing abt spark plugs is that the traditional ones are intended to have a clean chopped-flat central electrode.
With a new plug, its central electrode which comes down out of the porcelain bit, goes toward the curly grounding bit, and ends with a perfect flat surface.
The spark will always be between somewhere around the edge of the flat bit of the central electrode and the curly grounded bit.
There are machining tools in the precision-engineering trade which use exactly the same kind of spark to remove metal from their work pieces. An advantage of this kind of machining is that mild steel can be 'machined' just as easily as 'glass-hard' tool-steel. Material is removed from both the work-piece and from the electrode on the machine - but if the polarity (plus / minus) of the discharge is correct, most will be removed from the work-piece.
Same happens with a spark plug. The central electrode's nice flat edge is gradually spark-erroded into a nice rounded dome shape (the polarity of the applied spark voltage is arranged to reduce this effect).
A spark will most easily occur if a sharp point exists. The top edge of a 'cylinder' is close to being a sharp edge, a dome isn't. In a given situation, more voltage will be needed to make a spark begin where a dome is involved than where there is an edge or a point to help it.
The iridium plug on my DiBlasi folding motorcycle has a central electrode ending in a point. If that were done with an ordinary steel central electrode it would work very well, but would would quickly overheat, errode, and turn into a dome with the corresponding much bigger gap.
The irridium material can stand that situation without erroding excessively, and can provide a pointy bit to encourage a good spark in the first place.
It's possible to improve a conventional plug by getting a file onto the central electrode, filing it back flat, and then re-setting the gap.
This is all opinion. Does anyone see any holes in it?
I am no expert on spark plugs, but I just looked up a few pages trying to figure out more. The melting point of Iridium is high so that is a reason they use this metal for the electrode's sparking tip.
Also the tip does not have to be pointed. Here is another iridium plug.
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